In manufacturing a waterproof product, a seam structure plays an important role.
International Publication No. WO2011/091351 discloses a waterproof seam. A hydrophobic polymer membrane is provided into a seam by an application of a seam tape to provide a long seam.
However, a structure of the seam is rather complex. Further, the disclosed waterproof seam starts with laminated fabric requiring continuous stitching. Accordingly, in order to seal needle holes generated during the stitching, the seam disclosed in the related art requires a use of a seam tape. The use of the seam tape requires additional cost and labor. Accordingly, there is a demand for an alternative waterproof seam.
FIG. 1 illustrates a fabric structure which does not use a seam tape in the related art. In FIG. 1, a first outer fabric 1a and a second outer fabric 1b are cut according to a pattern of an item to be generated, and then the first outer fabric 1a and the second outer fabric 1b are bonded by stacking one side of the first outer fabric 1a on one side of the second outer fabric 1b and stitching a joint portion of the first outer fabric 1a and the second outer fabric 1b. This is referred to as a seam.
Further, a first inner fabric 2a and a second inner fabric 2b are cut according to the pattern of the item to be generated, and one side of the first inner fabric 2a is stacked on one side of the second inner fabric 2b after forming an adhesive layer 3 on each of the inner fabrics 2a and 2b. 
Further, the first outer fabric 1a and the second outer fabric 1b are bonded on the stacked first inner fabric 2a and second inner fabric 2b. 
The fabric structure in the related art of FIG. 1 has an effect in that a seam tape is not used.
However, the first inner fabric 2a and the second inner fabric 2b overlap, so that the completed fabric is thick. Further, rainwater and the like may permeate through the bonded portion of the first outer fabric 1a and the second outer fabric 1b and pass between the first inner fabric 2a and the second inner fabric 2b. 
Further, in the structure of the related art, the bonded portion may be easily separated during a cleaning process or wearing.